Electronic accumulator



' Aug 13,1946. V R,- E, MUMMA- 2,405,664

ELECTRONIC ACCUMULATOR Filed July 17, 19-41` Robert E. Mamma InventorHis Attorney Patented Aug. 13, 1946 UNITED STATES PATENT OFFICEELECTRONIC ACCUMULATOR Robert E. Mumma, Dayton, Ohio, assignor to TheNational Cash Register Company,

Dayton,

17 Claims.

This invention relates to a high-vacuum elec tron tube counting ring andmore particularly pertains to a plurality of high-vacuum tubes which areoperated sequentially in response to commonly-received electricpotential impulses.

The principal object of the invention is to provide a plurality oi morethan two high-vacuum electron tubes connected in an endless operativechain whereby, because of circuit characteristics, but one tube of thering may be conducting at any one time, and the tubes, when operated,are rendered conducting one at a time in endless chain sequence.

Another object of the invention is to provide means whereby a pluralityof more than two high-vacuum electron tubes are rendered conducting insequence one at a time in response to each of commonly-received electricpotential impulses.

Another object of the invention is to provide an electron tube countingring accumulator of data, utilizing more than two high-vacuum electrontub-es as data-representing devices, the tubes beingconnected in anendless operative chain whereby they are caused to be rendered operativeone at a time endless chain sequence, al1 the parts being stationaryexcept electrons moved by differences in potential.

Another object of the invention is to p-rovide means whereby receivedelectric impulses are divided by two and impressed upon the highvacuumelectron tube counting ring, one impulse for every two impulsesreceived, and means is further provided for determining, from the stateof the dividing means and the state of the ring of electron tubes, thetotal number of received impulses.

Another object of the invention is to provide two sensing points foreach tube of the counting ring, each of said points being aiected by theassociated tube and by the dividing means to determine whether theconduction in a tube of the ring represents the first or the secondimpulse received by the dividing means affecting said tube.

Another object of the invention is to provide a high-vacuum electrontube counting device having a ring of more than two tubes, said devicebeing responsive to electric impulses received at any intervals greaterone twenty-fivethousandth of a second.

Another object of the invention is to provide a novel method foraccumulating and storing numerical data in a denominational system ofnumerical notation.

2 Another object oi the invention is to provide two electron tubecounting rings of different denominational value and means to cause astep of operation in one ring on completion oi a cycle of steps in theother ring.

It has been known how to connect two highvacuum tubes in a triggercircuit for alternate operation in response to commonly-receivedelectric impulses, thus forming a ring of two tubes, but suchcircuitsare not adaptable for more than two tubes. This invention provides forjoining more than two tubes in an endless operative chain, utilizing anentirely new type of circuit from what has hitherto been known.

In the disclosed embodiment of the invention, which embodiment is not tobe deemed to limit the broad principles of the invention, each of thetubes of the novel ring is designated to stand for two possible items ofdata. The condition of conduction of a tube signifies the registrationof data, and consideration must be given to the conducting tube and tothe impulse-dividing means whereby to determine which of the twopossible items of data is represented by the condition of the conductionof a particular tube. It will be obvious that the counting ring tubesmay also be used to represent single items of data by eliminating thedividing means.

Five tubes have been provided in the disclosed ring, each of said tubesrepresenting two adjacent digits in a denominational order of thedecimal system of numbers. For instance, a tube may represent 8 and 9,or 9 and 0, 0 and 1, or l and 2, depending on whether 0 or l is deemedthe starting point of the ring. If one tube represents the digits 0 and1, the next tube of the ring represents the digits 2 and 3. Thecondition of conduction in a tube indicates that either of the twodigits it represents is registered. The condition of the dividing means,as to which one of two possible conditions is prevailing, determineswhich of the two digits is registered.

It is to be understood that the essential and underlying principle ofthe invention is to provide a circuit network for a plurality of morethan two high-vacuum electron tubes wherein only one tube can beconducting at a given time and wherein the tubes may be made to beconducting one at a time in sequence in response to each ofcommonly-received electric potential impulses. The particular embodimentdisclosing the invention pertains to counting or accumulating numericaldata using the decimal system.

``It is apparent, however, that the principles of the invention gobeyond the number oi the tubes used in this disclosure and thedesignation given to them, and go beyond the idea of using a tubeiive-tube counting ring, and an indicator means if? for translating thecondition of the tubes into the decimal system of numerical notation.

General description In the disclosure of the invention, a source ofelectric impulses to be counted must be specified, and, for theparticular embodiment herein disclosed, a source of sine wave impulsesis chosen, which wave source is indicated conventionally as beingimpressed on terminals and 2|. All potentials given are relative toground potential. Cathode heaters are shown conventionally. Terminal 2|is grounded. Terminal 20 is coupled through capacitor 22 to the controlgrid 23 of vacuum amplier tube 24, as, for instance, an 1852 type ofpentode, having a grounded cathode 28. The grid is negatively biased farbeyond cut-oir by being connected through resistor 25 of 50,000 ohms topotential divider resistance 2E connected between ground and a conductor21 given a negative potential of 180 volts. The anode is Connectedthrough. point 3| arid ree sistor 32 of 25,000 ohms to conductor 33given potential of 120 volts positive. The screen grid 34 is coupled toground through a capacitor 35 of :3.1i

4 microfarads and connected through resistor 33 of 50,000 ohms to .the12o-volt positive conductor 33. The suppressor grid 31 is grounded.Under these conditions, point 3|, due to resistor 32, drops in potentialfor each sine wave of over 15 volts impressed on terminals 20 and 2|, astube 24 is rendered conductive during a portion of the positive half ofthe sine wave.

The negative potential impulses impressed on point 3|, each of whichrepresents a sine wave, are fed through capacitors 38 and 39, oi 10micro-microfarads each, to the control grids 40 and 4I of-vacuum tubesTl and T2 respectively, said tubes being pentode ampliiiers which may beof the 1852 type mentioned, arranged in a trigger circuit byconductively coupling the anode of each .tube to the control grid of theother tube of the pair. Upon receipt of a commonly-received negativepotential impulse on the control grids 40 and 4I, the tubes will stablyassume a mode of operation in which one or the other of the tubes isconducting, awaiting the next commonly-received negative electricpotential impulse on their grids. Said stable mode of operation followsthe receipt of the impulse, which impulse causes the co-nduction in theconducting tube to cease, which cessation in turn causes conduction inthe other tube to commence, it being impossible to have both tubesconducting at the same time because of the nature of the couplingcircuit. The oathodes 42 and 43 of the tubes Ti and T2. respectively,are grounded by being connected to conductor 29, as are the suppressorgrid-s 44 and 45. The anodes 48 and 43 of tubes TI and T2, respectively,are connected through resistors 45 and 41, respectively. each of 5,000ohms, to the 120-volt positive conductor 33.

The screen. grids and |55 of tubes TI and T2, respectively, areconnected to the 120-volt positive conductor 33. The anode 48 of tube TIis 4 coupled through a resistor 50 of 50,000 ohms and a capacitor 5| of50 micro-microfarads, in parallel, to the grid 4I of -tube T2. The grid4I is connected through resistor 52 of 50,000 ohms to the -volt negativeconductor 21. 1n a like manner, the' anode 49 of tube T2 is connectedthrough resistor 53 of 50,000 ohms and capacitor 54 of 50micro-microfarads, in parallel, to grid 40 of tube TI. Grid 40 isconnected through resistor 55 of 50,000 ohms to the 180-volt negativeconductor 21. Under these conditions, on each negative impulse commonlyimpressed on grids 40 and 4|, the conducting tube, of tubes TI and T2,will be'rendered non-conducting, and the consequent rise in anodepotential will be impressed cn the grid of the other tube of the pair,

causing it to conduct. Such trigger tube circuits are well known andcomprise a two-tube vacuum electron tube counting ring. The negativepotential impulse occurring at the anode of either tube TI or T2 whencommencing to conduct is impressed on the grid oi the other of the pair,keeping it more negative than the critical point, which is 20 volts inthe type of tube used, until the mode of operation of the tubes ischanged.

From point |51, connected to anode 49 of tube T2, the change inpotential caused by resistor 41 each time tube T2 stops conducting isimpressed through capacitor 55 ci 10 micro-microfarads onto the controlgrid 51 of pentcde amplier 58, which may be of the GAG'Y type, said gridbeing normally negatively biased beyond the critical point of 30 voltsby being connected through resistor 59 of 50,000 ohms to the 18o-voltnegative conductor 21. Cathode 50 is connected through resistor 5| of25,000 ohms to the 180-volt negative conductor 21 and is coupled topoint 262 through capacitor 82 of 4 microiarads. Screen grid B3 isconnected to the 1Z0-volt positive conductor 33 through resistor 64 of3,750 ohms and is grounded through capacitor 55 of 4 microfarads. Anode65 is connected to the 1Z0-volt positive conductor 33 through resistor01 of 5,000 ohms. Suppressor grid 30 is connected to the cathode.

With the aforementioned connections, tube 53 acts as an overbiasedamplifier responsive by conducting on each p-ositive impulse impressedthrough capacitor 55, and hence responsive once for each two sine waveimpulses impressed on terminals 2| and 22 as tube T2 ceases conducting,thus constituting a means to divide the input sine wave impulses by two.Due to the resistance B1 in the supply conductor for anode 55, there isa drop in potential at point 03 each time tube 58 commences to conduct.The drop in potential of point E9 causes a sharp negative impulse to beimpressed on conductor 10 each time tube 58 starts conducting.

Tube TI may be rendered conducting by grounding its grid 40 bytemporarily closing switch 1| and then opening it. Hence, if tube Tl isthus rendered conducting, then, on the rst sine wave input impulseimpressed on terminals 20 and 2|, tube T is rendered non-conducting, andconduction commences in tube T2. On the second sine wave input impulseime pressed cn terminals 20 and 2|, tube T2 is rendered non-conducting,conduction commences in tube Tl, and a sharp negative impulse isimpressed on conductor 10.

Tubes 1, 3, 4, and 5 are highvacuum electron tubes of high mutualconductance each having an anode, a cathode, a control grid, a screengrid, and an electrode connected to the cathode for directing theelectron flow to the anode efiiciently. The GYBG type of tube issatisfactory for use in the particular embodiment of the inventionherein disclosed, but it will be apparent that the particularcharacteristics of the tube are not a fundamental part of the inventionand the invention is not limited in scope by the type of tube, by thescreen grid, by the electron-directing cathodes, or by the particularvalues of resistance and capacitance used with the tubes, as theessential operation may be accomplished by a triode vacuum electron tubehaving an anode, a cathode, and a control grid.

The cathodes 12, 13, 14, 15, and 16 are connected to ground conductor29, and screen grids 11, 18, 19, 80, and 8| are connected to conductor82, which has a positive potential of 30 volts applied thereto.

A capacitor 83 of 4 microfarads couples ground conductor 29 and thescreen grid supply conductor 82.

. Each of the anodes 84, 85, 86,81, and 88 is connected through a25,000-ohm resistor, numbered 89, 90, 9|, 92, and 93, respectively, to a290-volt positive supply conductor 94. The anodes are connected withone' another in an endless chain operative series by conductor 95, therebeing a 25,000-ohm resistor in the conductor 95 between each twoadjacent anodes of the series. Thus, resistor 96 connects anode 84 ofthe l tube to anode 85 of the 2 tube; resistor 91 connects the anode 85of the 2 tube to the anode 86 of the 3 tube; resistor 98 connects theanode 86 of the 3 tube to the anode 81 of the 4 tube; resistor'99connects the anode 81 of the 4 tube to the anode 88 of the 5 tube; andresistor |00 connects the anode 88 of the 5 tube with the anode 84 ofthe 1 tube. Connecting each two adjacent anodes, and forming part of theresistance mesh, are a pair of resistances, each of the pair being ofl100,000 ohms value, resistors |06 and |01 joining the anodes of tubes 1and 2, resistors |08 and |09 joining the anodes of the tubes 2 and 3,resistors ||0 and joining the anodes of tubes 3 and 4, resistors ||2 and||3 joining the anodes of tubes 4 and 5, and resistors ||4 and ||5joining tubes 5 and 1. From the juncture of each of the last-named pairsof resistors-namely, points 2|5, ||6, ||1, ||8, and ||9is a connectionthrough a resistor of 100.000 ohms, like resistors |20, |2|, |22, |23,and |24, to a negative potential supply conductor |25 of 320 volts. Byconnecting the anodes of the tubes 1, 2, 3, "4, and in such an endlesschain symmetrical resistance network formed of a ring of resistanceloops, with the potentials given the supply conductor and with the tubesspecified, a condition is set up whereby, if one of the tubes of theseries 1, 2, 3, 4, and 5 is conducting, the network, at pointssymmetrical to the point of connection to the anode of the conductingtube, has certain corresponding potentials due to the current flowthroughl the conducting tube. The resistance network being symmetricaland the anodes of the tubes 1, 2, 3, "4, and "5 being joined to thenetwork at points |0|, |02, |03, |04, and |05, respectively, in asymmetrical manner, the pattern of potential variations in the networkring is regular, but is stepped around the ring in sequence as the tubesbecome conducting in sequence in response to the received impulses, aswill be explained.

In the network ring of resistors, with no tube conducting, points likepoints |0|, |02, |03, |04,

and |05 will have a positive potential of about 247 volts. Such apossibility is non-existent, except momentarily, in the circuit shown,as one tube will always be conducting due to the particular relativepotentials used, one of the tubes becoming conducting accordingly as ithas a tendency toward conductivity because of its varying in that mannerfrom absolute perfection more than the other tubes. On application ofpotentials to the supply conductors, and as one of the tubes becomesconducting before the others, there will be caused, by reason of thecurrent flowing through the tube, a readjustment of potentials of points|0|, |02, |03, |84, and |05. Assuming that the 3 tube is conducting,which may be assured by temporarily closing switch |26, thus groundinggrid |21, with the particular operating potentials applied to the supplyconductors, the potential of point |03 and the anode 88 of the 3 tubewill be about '7 volts positive with relation to the grounded cathode14, as the internal potential drop of a 6Y6G tube is about '7 volts.

The potential of points |02 and |04, representative of the anodes and 81of the tubes 2 and 4 respectively, will become about 122 volts positive,and the potential of points |0| and |05, representative of the anodes 84and 88 of the tubes 1 and 5 respectively, will become about voltspositive. Under these conditions, point ||9, connected to grid |21 ofthe 3 tube by means of conductors |28 and |29, assumes the potential ofground, rendering tube 3 highly conducting. At the same time, thepotential of -the control grid of tube l is the same as point 1, beingconnected thereto by conductors 263 and 264, which point is 60 voltsnegative with respect to ground; the grid of tube 2 is of the samepotential as point ||8, being connected thereto by conductors 265 and256, which point ||8 is 14 volts negative with respect to ground; thegrid of tube 4 is of the same potential as point 2|5, being connectedthereto by conductors 261 and 258, which point 2|5 is 14 volts negativewith respect to ground; and the grid of tube 5 is of the same potentialas point H6, being connected thereto by conductors 269 and 210, whichpoint l i6 is 60 volts negative. Thus, the two tubes adjacent in bothdirections in the sequence to 'the conducting tube have their gridsnearer the critical point, which point is about 10 volts negative, thanthe grids of the tubes farther away in the sequence.

The input conductor 10, as explained, carries a negative potentialimpulse each time tube 53 is conducting, which impulse is impressedthrough capacitors |30, |3|, |32, |33, and |34, each of 50micro-microfarads capacity, onto the grids of all of the tubes 1, 2, 3,4, and 5 simultaneously. The attenuated input negative impulsesimpressed on the control grids are of about 20 volts. A negative impulseimpressed on conductor 10 as the 3 tube is conducting will render the 3tube non-conducting, and the consequent positive potential surge atpoint 103 will be impressed on capacitors |35 and |36, each of 50micro-microiarads capacity. The positive potential surge cannot causeconduction between anode l35 and cathode |31 of double diode rectiertube |40, which may be of the SHG type, because it is of the wrongpolarity, and the surge is attenuated as it passes through resistor |38of l megohrn, so it does not cause enough of a positive potentialimpulse on the grid |4| of the 2 tube, to which resistor |38 isconnected, to cause tube 2 to conduct. The positive potential surgethrough capacitor |35 is impressed on anode |42, causing a positivepotential surge at point |43 of 40 volts, due to resistor I 20, whichsurge makes the grid |45 of the 4 tube more positive than the criticalpoint, thus causing the 4 tube to become conducting. As tube "4 becomesconducting, point |04 has a potential surge toward the negative from |22volts positive to 7 volts positive. This negative surge is impressed oncapacitors |45 and |41, causing conduction to occur between cathode |40and anode |49, causing a strong negative potential impulse to beimpressed on grid |21 of tube 3, preventing it from again conducting dueto the change in potential of point I2 from 122 volts positive to 160volts positive which is impressed on grid |21 by way of the associatedrectier tube. Thus, the potential surges in the anodes of the tubes 1,2, 3, 4, and are utilized in conjunction with the rectiiers to cause thesequential operation to be in one direction only.

On the next negative potential impulse received commonly by the tubes 1,2, 3, 4, and 5, the 4 tube will be rendered nonconducting, and the 5tube will be rendered conducting. After the 5 tube, the 1 tube will berendered conducting. This will occur in endless chain sequence, theendless chain of tubes being receptive and accurately responsive to morethan 12,500 steps of operation per second with the values of resistorsand capacitors, the type of tubes, and the potentials disclosed. Thismeans that 25,000 potential impulses per second may be fed intoterminals 20 and 2|, and the state of the tubes TI and T2 in conjunctionwith the state of the tubes 1, 2, 3, 4, and 5 may be sensed toaccurately count up to ten the number of potential impulses received ata frequency of 25,000 per seco-nd.

t is apparent that another ring of tubes like tubes 1, 2, 3, 4, and "5may be actuated in conjunction with another impulse divider like tubesTI and T2 wherey they are made to operate a step in sequence each timethe ring shown in the drawing completes one sequential cycle. As theinput to tubes of a trigger circuit like tubes T| and T2 requires anegative electric potential impulse for a step of operation, a conductorconnected to point 15| will have impressed thereon a negative impulseeach time tube 1 begins to conduct, such negative impulse may beutilized for actuating another ring by one step by being connected to apoint corresponding to point 3|. Other rings may be connected to theproposed second ring in order to obtain a plural denominational systemof any number. As many rings may be used in series as are required forthe particular purpose for which the system is to, be adapted.

The means for sensing the condition of the divider tubes Ti and T2 andthe counting ring tubes 1, 2, 3, 4, and 5 comprises a resistance networkfor each counting ring tube, one part of each of the resistance networksbeing connected to the anode of tube Tl and the other part of each ofthe resistance networks being connected to the anode potential of tubeT2, and the mid-part of each of the resistance networks being aiected bythe anode potential of the associated counting ring tube. Point |50,having the potential of anode 84 of tube 1, is connected throughresistor |5| of 1,500,000

ohms, point |54, and resistor |52 of 500,000 ohms to conductor |53,which is connected to the point |10. Point |50 is also connected throughresistor |55 of 1,500,000 ohms, point |56, and resistor |58 of 500,000ohms to conductor |18, which is connected to the point |15. Each of thepoints |59, |00, |5I, and |52 is connected to conductors |53 and |18 inthe same manner as has been explained for point |50. From point |54 aconductor |63 extends to a l contact |04 on a commutator |55, and frompoint |56 a conductor |56 extends to a 2 contact |10 on commutator |55.Point |10 is connected through resistor 1| of 850,000 ohms to a 400-volt negative terminal |12 and is connected through resistor |13 of500,000 ohms to point |14, which has the same potential as anode 48 ofthe tube Tl, and conductor |10 is connected to point |15, which point isconnected through resistor H10 of 850,000 ohms to a terminal of 400volts negative potential and is connected,

through resistor |11 of 500,000 ohms to point |51, which has thepotential of the anode 4S of the tube T2.

If the l tube is conducting, its anode 84 will be at 7 volts positivepotential, and, if it is not conducting, it will be at 122 volts or 160volts positive potential. If, while the 1 tube is conducting, tube T| isconducting, anode 04 therefore being about '7 volts positive potential,then point |54 and contact |64 will be about 17 volts negativepotential. If tube TI is not conducting, then its anode is about 90volts positive, and point |54 will be at 2 volts positive potential,whereas point |56 will be at 17 volts negative potential because tube T2is conducting and its anode is at 23 volts positive. If point |50 wereat 122 or 160 volts positive potential, as would be the case if tube 1were not conducting and TI were conducting, then points |54 and |56would be 12 volts positive and 21 volts positive potential respectively.Consequently, the most negative contact or 2 on commutator |65represents the registered number. The same changes in potential towardthe negative Will occur on the other contacts of the commutator if theassociated tube of the ring is conducting.

Vacuum tube |68 having a grounded cathode is of the same type as tube "1having a critical grid potential of 10 volts negative, and consequently,when sensing arm |69 is caused to move over commutator by means offriction drive 21|, which moves axle |I1| (indicated by the dottedlines), if a contact is sensed having such critical potential or apotential more negative than the critical potential, conduction willstop in the tube |68, deenergizing solenoid |90 normally energize-d byconduction through tube |00,

Ywhich allows the spring to move the pawl |8| so as to stop the sensingarm |09, the wheel indicator |82, and the axle ||1|, to which the Wheeland the sensing arm are secured, against the action of friction drive21|y thus positioning the indicator Wheel |02 corresponding to thevposition of the sensing arm |69, and consequently not only indicatingwhich of the tubes 1, 2, 3, 4, and 5 is conducting, but also indicatingwhich of the tubes T| and T2 is then conducting. The change of potentialof the commutator contacts, such as contact |54, when they are no longersulciently negative causes conduction to comience in tube |58, whichretracts pawl ISI, causing arm |60 to hunt another contact of the propernegative potential, and no contact has the proper potential unless thetwo tubes associated therewith are conducting.

It is thus possible, by the impression of sine Waves upon the terminals2li and 2| in any number up to ten, to diiierentially actuate the tubes1, 2, 3, 4, and 5 in conjunction with the tubes T and T2 so as to countand indicate the exact number oi sine waves received. The waves may beimpressed upon the terminals 26 and 2l at regular or irregular intervalsand at frequencies as great as 25,000 per second. It has also beendescribed how to construct a plural denominational high-vacuum tubecounting device for accommodating larger accumulations of data.

Although the circuit is shown for operation by an input of sine waves,it is perfectly apparent that any means of actuating tube 24 orimpressing the proper potential impulses on point itil or on conductor'I is within the scope of the invention, and it is to be further notedthat the kind of tubes used, the particular values of potentials andvalues of circuit elements employed, or the impulse dividing means shownare not limiting factors as to the high-vacuum tube counting ring, butmerely show one practical embodiment of the invention. This and otherembodiments or" more or fewer tubes in the ring are within the scope ofthe invention as set forth in the claims which follow. Y

What is claimed is:

1. In combination, a plurality of more than two anode-cathode electrodepairs each in a vacuum; means supplying operating energy to theelectrode pairs, said means including a ring of resistors, meansconnecting the anodes to symmetrical points in the ring, and resistanceconnections from said points to a common source of electric potential;and a control means for each of the electrode pairs each joined to theringof resistors at a point diametrically opposite to the associatedanode connection.

2. In combination, a plurality of more than two high-vacuum electrontubes each having an anode, cathode, and a control grid; a ring of fresistors; means connecting the anodes to symmetrical points in the ringin sequence; resistanceconnections from said points to a common sourceof electric potential, the act of conduction in a tube causing asymmetrical variation of potential in the ring of resistors; means forinitiating conduction in a tube; means connecting each control grid to aplace in the ring of resistors whereby if conduction in any tube occursthe grids of the other tubes will be so strongly potentially biased thatno conduction can occur therein and whereby one and only one tube willalways be conducting; means for causing conduction to cease in anyconducting tube, the change in potentials around the ring of resistorscausing the next adjacent tube in the series to become conducting; andmeans furnishing a potential impulse to the control grid of the tubenext in the sequence to the tube rendered nonconducting to aid itscommencement of conduction.

3. In combination, a plurality of more than two high-vacuum electrontubes each having an anode, a cathode, and a control grid; means forsupplying cathode energy to the tubes; common electric network meanscomprising a symmetrical network of resistors arranged ina ring forsupplying anode energy to the tubes, said anodes being connected to thering serially in symmetry,

the condition of conduction in a certain tube causing a correspondingsymmetrical set of potentials at the anode connection points in thering; means for initiating conduction in a tube; means connecting eachcontrol grid to a place in the ring whereby if conduction in any tubeoccursthe grids of the other tubes will be so strongly potentiallybiased that no conduction can occur therein and whereby one and only onetube will always be conducting; means for causing conduction to cease inany of the tubes, the change in potentials of the ring of resistorscausing the next adjacent tube in the series to become conducting; andmeans electrostatically coupling the anode of a tube and the controlgrid of the tube next in series thus aiding the sequential operation ofthe tubes.

4. In combination, a plurality of high-vacuum electron tubes each havingan anode, a cathode, and a control grid; means to supply cathodepotential to the tubes; common means including a symmetrical mesh ofresistors for supplying anode potential to the tubes, said anodes beingconnected symmetrically therethrough to the source of potential, meansfor biasing the grids of the tubes with a potential normally preventingconduction through the tubes, said biasing means including connectionsof the grids to symmetrical points in the mesh of resistors so that ii'a tube is conducting the grids of the other tubes will be given apotential more negative than normal but those two tubes immediatelyadjacent to the conducting tube as regards their anode connections tothe resistor mesh being given less additional negative potential thanthe grids of the other non-conducting tubes; and means coupling theanode of keach tube to the grid of each or the adjacent two tubes sothat when conduction commences in a tube it causes a sharp negativepotential impulse to be impressed on the grid of one of the adjacenttubes and when conduction ceases in a tube it causes a sharp positivepotential impulse on the grid of the other of the adjacent tubes.

5. In combination, a plurality of high-vacuum electron tubes each havingan anode, a cathode, and a control grid; means to supply cathodepotential to the tubes; common means including a symmetrical mesh ofresistors for supplying anode potential to the tubes, said anodes beingconnected symmetrically therethrough to the source or" potential; meansfor biasing the grids of the tubes with a potential of a value normallypreventing conduction through the tubes if another tube is conducting,said biasing means Y including connections oi' the grids to symmetricalpoints in the mesh of resistors so that if a tube is conducting thegrids of the other tubes will be given a potential more negative thannormal but those two tubes immediately adjacent to the conducting tubeas regards their anode connections to the resistor mesh being given lessadditional negative potential than the grids of the other non-conductingtubes; means connecting the anode of each tube to the grid oi each ofthe adjacent two tubes so that when conduction commences in a tube itcauses a sharp negative potential impulse to be impressed on the grid ofone of the adjacent tubes and when conduction ceases in a tube it causesa sharp positive potential impulse on the grid of the other of theadjacent tubes; and means to impress a negative potential impulse on thegrids of all the tubes sufficient to stop conduction in any conductingtube thereby causing the adjacent tube whose grid receives the positivepotential impulse to 11 commence conduction and in turn cause a negativepotential impulse on the grid of the tube that stopped conduction.

6. In combination, a plurality of more than two high-vacuum electrontubes each having an anode, a cathode, and a control element; a commonelectric energy supply means for the anodes of said tubes including anetwork of resistors` arranged in a ring to which the anodes aresymmetrically connected forming an endless operative chain; meansconnecting each anode through a resistance to a common anode potentialsource; and means electrostatically coupling each anode to the controlelements of the tubes immediately adjacent in the sequence, said meansincluding a rectifier and capacitor in series in each coupling so thatpositive potential surges in an anode are conveyed to the controlelement in the tube next in the operative sequence and so that negativepotential surges of an anode are conveyed to the control element of thetube preceding in the operative sequence.

7. In combination, any plurality of more than two anode-cathode pairs; acontrol means for each pair; means to supply cathode energy to thepairs; means to supply anode and control energy to the pairs, said meansincluding a ring of resistors to which the anodes and the vassociatedcontrol members are symmetrically electrically connected, an anode andits control member being diametrically connected to the ring; and aresistance connection between each anode and a common source of anodepotential.

8. In combination, a series of resistors connected in a ring; resistancemeans connecting symmetrical points in the ring to a common anodepotential supply conductor, there being two resistors between each-twoadjacent anodes; a plurality of high-vacuum electron tubes connected bytheir anodes to said points and connected by their cathodes to a sourceof cathode potential; means connecting the jointure of each twointer-anode resistors to a source of negative potential; a controlelement for each tube connected to the jointure between the tworesistors farthest away in the ring from the point to which theassociated anode is connected; and a common input conductor coupled toeach control member.

9. In combination, a plurality of electron tubes; circuits connectingthe tubes so that they are operated one at a time in sequence inresponse to each of a plurality of electric impulses commonly impressedon said tubes at regular or irregular intervals; means to divide thenumber of introduced impulses by two, said dividing means producing anoutput impulse for every two introduced impulses; means to impress theoutput of said impulse divider on said tubes so as to cause a step ofsequential operation for each two produced impulses; two sensingstations for each tube and means to couple the tubes, the sensingstations, and the dividing means whereby it may be determined which oneof the introduced impulses is represented by the state of conduction ofany tube of the plurality, said means including a resistance networkaffected by the` state of conduction in the tubes of the sequence and bythe state of the dividing means which determines the electric potentialat various points in said resistance network.

l0. In combination, two high-vacuum electron tubes arranged in a triggercircuit so that but one tube of the two may be conductive at any onetime and whose mode of operation may be changed by each of negativepotential impulses impressed thereon; a high-vacuum electron tube relaycaused to conduct each time the tubes oi the trigger circuit changes toa particular mode of operation, the act of conduction of said lastnamedtube causing a negative electrical potential impulse, each of saidlast-named impulses representing two of the impulses impressed 0n thetrigger pair; a plurality of electron tubes arranged in a circuit foroperation in endless chain sequence one at a time, which tubes arecaused to operate step by step in response to each of received negativeelectric potential impulses; means to impress the trigger pair producednegative impulses on said tubes whereby each step of operation of theendless chain represents two 0f the impulses impressed on the triggerpair; and means coupling the tubes of the endless chain of tubes and thetwo trigger connected tubes in a resistance network so that the state ofconduction of one tube of the endless chain and of one or the other ofthe trigger tubes causes a sensible change in potential at one or theother of associated points in the resistance network,

ll. In combination, means for converting introduced sine wave electricpotential impulses into negative electric potential impulses; twohighvacuum electron tubes arranged in a trigger circuit so that but onetube of the two may be conductive at any one time and whose mode ofoperation may be changed by each of the negative impulses produced bythe converting means; a high-vacuum electron tube relay caused toconduct each time the tubes of the trigger circuit changes to aparticular mode of operation, the act of conduction oi said last-namedtube causing a negative electrical potential impulse in anvoutputcircuit, each of said last-named impulses representing two of theimpulses from the sine wave source; a plurality of vacuum electron tubesarranged in a circuit for operation in endless chain sequence one at atime, and caused to operate step by step in response to each of receivednegative electric potential impulses; means to impress the relayproduced negative impulses on said tubes whereby each step of operationof the endless chain represents two of the introduced sine waveimpulses; and means to couple the tubes of the endless chain or tubesand the two trigger connected tubes in a resistance network whereby thestate of conduction of one tube of the endless chain and of one or theother of the trigger tubes cause a sensible change in potential in oneor the other of two associated points in the network.

l2. In combination, a plurality of high-vacuum electron tubes connectedin an endless operative chain wherein they are rendered conductive one-at a time in sequence in response to each of commonly-received electricimpulses; an electric impulse dividing means including two electrontubes which are rendered conductive in alternate succession and eitherof which electron tubes may be conductive at the same time any one ofthe highvacuum electron tubes is conductive; two electric terminalsassociated with each of the high-vacuum tubes, one of said terminalsbeing associated with a high-vacuum tube and one of the aforesaid twoelectron tubes and the other terminal being associated with thehigh-vacuum tube and the other of said two electron tubes; meansconnecting said terminals to said associated tubes, said means includingresistances in said connections so that the potential of a terminal willchange when the associated tubes change their state of conduction; andmeans automatically exploring the terminals for one whose potential isV13 determined by the conducting condition of the two tubes associatedtherewith.

13. In combination, a plurality of high-vacuum electron tubes connectedin an endless operative chain-wherein they are rendered conductive oneat a time in sequence in response to commonlyreceived electric impulses;an electric impulse dividing means including two electron tubes whichare rendered conductive in alternate succession by received electricimpulses and either of which electron tubes may be conductive at thesame time any one of the high-vacuum electron tubes is conductive; twoelectric terminals associated with each oi the high-vacuum tubes, one ofsaid terminals being associated with a highvacuum tube and one of theaforesaid two electron tubes and the other terminal being associatedwith the high-vacuum tube and the other of said two electron tubes;means connecting said terminals to their associated tubes so that thepotential of a terminal will indicate whether both the associated tubesare conducting or not; means automatically exploring the terminals forone potentially affected by conduction in both its associated tubes; andmeans to stop the exploring when the terminal is sensed. that has apotential indicating the condition of conduction of both the associatedtubes.

14. In combination, a plurality of high-vacuum electron tubes eachhaving an anode, a cathode, and a control grid; means to supply cathodepotential to the tubes; means including a symmetrical mesh of resistorsfor supplying anode potential to the tubes, said anodes being connectedsymmetrically therethrough to the source of potential forming an endlessoperative sequence; means for biasing the grids of the tubes with apotential tending to prevent conduction through said tubes, said biasingmeans including connections oi the grids to symmetrical points in themesh of resistors so that if a tube of the plurality is conducting thegrids of the other tubes will be given a negative potential thatprevents conduction in the associated tube, those two tubes immediatelyadjacent to the conducting tube as regards their anode connections tothe resistor mesh being given less negative potential than the grids ofthe other nonconducting tubes; means coupling the anode of each tube tothe grid of each of the adjacent two tubes of the sequence so that whenconduction commences in a tube it causes a sharp negative potentia1impulse to be impressed upont he grid of one of the adjacent tubes andwhen conduction ceases in a tube it causes a sharp positive potentialimpulse on the grid of the other adjacent tube; and means to impress anegative potential impulse on the grids of al1 the tubes suiiicient tostop conduction in any conducting tube thereby causing the adjacent tubewhose grid receives the positive potential impulse to commenceconduction and in turn by its commencing to conduct causing a negativepotential impulse to be impressed on the grid ci the tube that stoppedconduction.

15. In combination, a plurality of high-vacuum electron tubes eachhaving an anode, a cathode, and a control grid; means to supply cathodepotential to the tubes; means including a symmetrical mesh of resistorsfor supplying anode potential to the tubes, said anodes being connectedsymmetrically therethrough to the source of potential, forming anendless operative chain of tubes; means for biasing the grids of thetubes with a potential tending to prevent conduction through said tubes,said biasing means including connections of the grids to symmetricalpoints in the mesh of resistors so that if a tube is conducting, thegrids ofthe other tubes will be given a negative potential that preventsconduction in the associated tube, those two tubes immediately adjacentto the conducting tube as regards their anode connections to theresistor mesh being given less negative potential than the grids of theother non-conducting tubes; means coupling the anode of each tube to thegrid of each of the adjacent two tubes of the sequence so that whenconduction commences in a tube it causes a sharp negative potentialimpulse to be impressed upon the grid of one of the adjacent tubes andwhen conduction ceases in a tube it causes a sharp positive potentialimpulse to be impressed on the grid of the other adjacent tube; andmeans t0 impress a negative potential impulse on the grids of all thetubes suicient to stop conduction in any conducting tube thereby causingthe adjacent tube whose grid receives the positive potential impulse tocommence conduction and in turn cause a negative potential impulse onthe grid of the tube that stopped conduction; a high-vacuum electronampliiier tube having a resistance in its anode, which tube is caused toconduct at intervals; and means connecting the anode of the amplifiertube to the impressing means.

16. In combination, ive high-vacuum electron tubes each having an anode,a cathode, and a control grid; means to supply cathode potential to thetubes; means connecting said five tubes in an endless operative chainseries, said means including a symmetrical mesh of resistors forsupplying anode potential to the tubes, said anodes being connectedsymmetrically therethrough to the source of potential and said meansalso including means for biasing the grids of the tubes with a potentialtending to prevent conduction through the tubes by connection of thegrids to symmetrically located points of the mesh of resistors and to asource of negative potential so that ii a tube is conducting, the gridsof the other tubes will be given a potential more negative than normaland those two tubes immediately adjacent in the chain to the conductingtubes as regards their anode connections to the resistor mesh will begiven less additional negative potential than the grids of the othernon-conducting tubes of the Chain; means including couplings between theanode of each tube and the grids of each of the adjacent two tubes inthe chain so that when conduction commences in a tube it causes a sharpnegative potential impulse to be impressed on the grid of one of theadjacent tubes and when conduction ceases in a tube it causes a sharppositive potential impulse on the grid of the other of the adjacenttubes; means coupling the grids of all the tubes electrostatically to acommon conductor; input terminals; means for causing a single negativepotential impulse for each sine wave received on said terminals; twohigh-vacuum electron tubes arranged in a trigger circuit; means forimpressing the negative impulses on the trigger circuit tubes so thateach negative impulse received changes the mode of operation of thetrigger circuit tubes; an amplifier electron tube having a control grid;means to overbias the control grid to normally prevent conduction in theampliiier tube; means connected with one of the trigger tubes so thatwhen said trigger tube ceases conducting a sharp positive potentialimpulse is impressed on the grid of the overbiased amplifier tube,causing it to conduct temporarily; a resistance in the anode circuit ofthe anode conductor of the overbiased amplifier; and means connectingthe anode of the overbiased amplier to the electrostatic coupling meanswhereby the series of the ve tubes is caused to take a step in thesequential operation on each two received sine wave impulses. Y

17. In combination, a plurality of electron tubes; circuits connectingthe tubes so that they are operated one at a time in sequence inresponse to each of a plurality of potential impulses impressed thereon;means having two modes of operation to divide the number of introducedimpulses by two, said, means changing its mode of operation on each ofintroduced potential impulses; means to impress an impulse on said tubeswhen the divider assumes a certain one of its modes of operation so asto cause a step of sequential operation for each two impulses introducedinto the divider; a plurality of sensing stations; and means including aresistance network coupling each of the tubes and the dividing means toan associated two of the sensing stations so that a particular one ofthe two sensing stations represents and has an electric potentialdetermined by the conduction in a tube and one of the modes of operationof the dividing means and the other of the sensing stations representsand has an electric potential determined by the conduction in the saidtube and the other mode of operation of the dividing means.

ROBERT E. MUMMA.

